The present invention relates to a power tool and has particular although not exclusive, relevance to battery powered tools.
It is conventional for power tools to be designed and built for a dedicated purpose, such as a drill, ajigsaw or a sander. If the user needs to undertake a sanding operation he will use a dedicated sander. If then he needs to drill a hole in a workpiece he will swap the sander for a dedicated drill, and so on.
Whilst such swapping over of dedicated tools is not inconvenient, it does mean that, particularly for the person who needs to use power tools relatively infrequently, considerable expense is incurred in acquiring a broad range of these dedicated power tools.
Furthermore, in the case of so-called xe2x80x9ccordlessxe2x80x9d or battery-powered tools, the user will either need to change the battery pack when changing dedicated tools, or have several ready-charged batteries available for use. These alternative options are cumbersome or expensive respectively.
Solutions to the above problems have been proposed in the past and one such solution entails providing a power tool including a motorised drive which is capable of accepting any one of a plurality of discrete heads which achieve a dedicated purpose. This means that rather than purchasing a dedicated entire power tool for each job, the user only has to purchase a dedicated head (which is cheaper than a dedicated entire tool) and just swap these over as and when necessary.
There still exist certain problems with such solutions, however. In a system such as the discrete heads described above, it is important to ensure a sufficiently secure and rigid attachment between the power tool and the dedicated head. While it is of course necessary to provide a sufficiently secure attachment for all heads, it is particularly important to do so where the nature of the work for which the assembled tool is to be used is likely to generate high forces, in particular relatively high bending and twisting forces between the power tool and the head.
It is an object of the present invention to provide a power tool in which the above disadvantages are reduced or substantially obviated.
The present invention provides a power tool including a body portion defining a handle and a motor mounted within the body portion, which motor is arranged to drive an output spindle of the tool; the body portion further defining an opening around the output spindle, which opening accepts any one of a plurality of attachment heads presented thereto, the power tool characterised in that there is an interface between the body portion of the power tool and the attachment head, and this interface is shaped so that the attachment head is supported in three dimensions.
In a preferred embodiment of a tool according to the invention, the interface between the body portion and the attachment head comprises a first linear section remote from the handle and a second cylindrical section adjacent to the handle.
The linear/cylindrical interface gives added stability as the applied force from the operator""s hand acts through the curved intersection. Further, the cupped nature of the intersection provides additional support to any torque reactions when the tool is in operation, for example as either a drill, driver, saw or sander mechanism.